Effects of the limiting corneal cell layers on the integrity of stromal architecture and the state of stromal dehydration is under investigation. In order to provide a rationale for the therapeutic control of traumatic and/or pathophysiologically induced stromal destruction as well as for the preservation of donor tissue, the potential capacity of epithelial enzymes to degrade stromal macromolecules is under investigation. Structural modification of chemically characterized proteoglycans, glycoproteins and collagen of the stroma by the near-neutral and acidic enzymes of the respective soluble and particulate fractions of the epithelium is evaluated by biochemical techniques. Elucidation of mechanism(s) located in the endothelium that effect stromal dehydration can provide the means for prolonging the viability of donor tissue, facilitating the apposition of transplants and the formulation of irrigating solutions. Particular emphasis is given to metabolities that by measured physiological and biochemical parameters prove beneficial to trasendothelial fluid transport (viz., disulfide compounds with the cystinyl moiety) in a study designed to discriminate between interaction with the cellular membrane and intracellular metabolism.